Hi.what is the output and why?(c++)

Question

#include<iostream>
using namespace std;
void main(){
int i = 5;
cout << i;
}

Answer 1

yeah main function should be int and return any value like 0

#include<iostream>
using namespace std;
int main(){
int i = 5;
cout << i;
return 0;
}

Answer 2

yeah return 0; is not necessary it will work fine without it too but it is written literally because every function returns an value

Answer 3

ohhh! main function can not be void!!!
this is reason of error!!!

Answer 4

but i think return 0; is not necessary and will work without it. is it true?